December 6, 2008
Lamisa Haque
Math 7b Big Idea Many things in our world are mathematically similar and we can use this to understand and describe the world around us. Essential Question # 4/5 - What types situations can I use my similarity ideas to solve?
Mr. Anwar's class is using the shadow method to estimate the height of their school building. They have the following measurements and sketch:
Length of meterstick: 1 m
Length of the meterstick's shadow: 0.2 m
Length of the building's shadow: 7 m A. Use what you know about similar triangles to find the building's height from the given measurements. Explain your work.
First we had to find the scale factor from the shadow of the meterstick to the shadow of the building. We did this by dividing 7m (shadow of building) with 0.2m (shadow of meterstick) and we got 35, so that is the scale factor. This means that the height of the building is 35 m.
B. With your class, choose a building or other tall object. Work with a group to estimate the object's height using the shadow method. Mr. Cooper said to make a random estimate. My partner and I said 12 meters. Then we made a sketch like this:
Our procedure was: 1. Measure Shadow A. 2. Measure Shadow B. 3. Come back to class. 4. Calculate the scale factor from A to B. 5. Use what we know to calculate C.
So we went and got the measurements. Here they are: Shadow A: 1.08 m Shadow B: 12.72 m
Then we calculated the scale factor from A to B and we got 11.78. Therefor, it means that the height of the the building was 11.78. Scale factor: 11.78 m Height of C: 11.78 m
Follow Up We never made a line plot so I could not put it on here.
Lamisa Haque
Math 7b
Big Idea
Many things in our world are mathematically similar and we can use this to understand and describe the world around us.
Essential Question # 4/5 - What types situations can I use my similarity ideas to solve?
Mr. Anwar's class is using the shadow method to estimate the height of their school building. They have the following measurements and sketch:
Length of meterstick: 1 m
Length of the meterstick's shadow: 0.2 m
Length of the building's shadow: 7 m
A. Use what you know about similar triangles to find the building's height from the given measurements. Explain your work.
First we had to find the scale factor from the shadow of the meterstick to the shadow of the building. We did this by dividing 7m (shadow of building) with 0.2m (shadow of meterstick) and we got 35, so that is the scale factor. This means that the height of the building is 35 m.
B. With your class, choose a building or other tall object. Work with a group to estimate the object's height using the shadow method.
Mr. Cooper said to make a random estimate. My partner and I said 12 meters. Then we made a sketch like this:
Our procedure was:
1. Measure Shadow A.
2. Measure Shadow B.
3. Come back to class.
4. Calculate the scale factor from A to B.
5. Use what we know to calculate C.
So we went and got the measurements. Here they are:
Shadow A: 1.08 m
Shadow B: 12.72 m
Then we calculated the scale factor from A to B and we got 11.78. Therefor, it means that the height of the the building was 11.78.
Scale factor: 11.78 m
Height of C: 11.78 m
Follow Up
We never made a line plot so I could not put it on here.